Abstract

The reaction of with has been studied by electron energy-lossspectroscopy at . In addition to the losses due to Si–O–Si configurations, we observed two Si–O stretch modes depending on the coverage. A peak appears at the initial reaction stage and was ascribed to a metastable product with one oxygen atom bonding on top of Si adatom and the other inserted into the backbond. The initial product is further oxidized to produce the second Si–O stretch peak at . The secondary product was partially substituted with isotopes and analyzed with a simple model of coupled oscillators. The vibrational spectra reflect dynamical couplings between the isotopes, which is consistent with those predicted from the tetrahedral structure with one on top and three inserted oxygen atoms.